Switch actuator utilizing a spring accumulator



Sept. 9, 1958 I w. BILLETER SWITCH ACTUATOR UTILIZING A SPRING ACCUMULATOR Filed Aug. 20, 1956 Unite States SWITCH ACTUATOR UTILIZING A SPRING ACCUMULATOR Walter Billeter, Baden, Switzerland, assignor to Aktiengesellschaft Brown, Boveri & Cie., Baden, Switzerland, a joint-stock company This invention relates to improvements in the art of actuating switches by means of accumulators.

For the connection of circuit breakers and power switches there are frequently used spring members which are tensioned by hand or by means of a motor. These members are held fast mechanically in a tensioned state by latches. These latches are released by the tripping control so that the shifting is effected by the disengagement of the accumulator. Such devices are provided, in the hitherto known constructions, separately for the connections and for the disconnections. This necessitates a separate mechanism for the connection and disconnection operations. Said mechanism requires considerable space and complex arrangements. In addition, means are required for obtaining the correct sequence of the switches and the desired tensioning.

effected by the switching process of the accumulator of the respective opposite switching operation. However, large dimensioning of the necessary accumulator springs is required in such cases since they must simultaneously switch and strain.

A practical simplification is now attained according to the invention in that the connection and disconnection operations are elfected by identical accumulators without any additional tensioning between switchings. According to the invention the accumulator works with a gear which is coupled with the driving shaft of the switch, which driving shaft rotates during the disengagement of the accumulator. In'addition, the gear is combined with a pulling member, for example, a motor or a crank, which tensions the accumulator. Both motions are performed independently of each other so that the tensioning member remains at rest during the switching operation and, inversely, the switch shaft remains in its respective position during the tensioning operation.

The number of the necessary details has been reduced according to the present invention. Only one spring is required, which single spring is tensioned only once and then is available for connections and disconnections. In this case, it is also feasible to perform several switching series without any intermediate spring tensioning. Such gearings may also be used for the short interruption wherein a disconnection, a connection and, under certain circumstances, again a disconnection must be performed within short intervals. To make this possible, there is utilized only a part of the entire spring lift for each switching. Accordingly, means must be provided for maintaining the gearing mechanism in intermediate positions.

To make feasible the oppositely directed switching motions by the accumulator, moving in the same direction, there are required special gears. The construction of these devices is more secifically explained in the following specification with reference to the appended drawing, in which:

atent ice Fig. 1 diagrammatically illustrates a simple embodiment of the invention;

Fig. 2 shows a modification of the embodiment illustrated in Fig. l, in which an electric motor is employed as driving member;

Fig. 3 illustrates the use of different latching means in the general organization of Fig. 2;

Fig. 4 illustrates the use, in the general organization, of special means for providing a relatively great torsional moment for disconnection while a relatively smaller torsional moment is necessary for engagement.

Fig. 1 shows the connection of the accumulator or closing spring cylinder 1 with the gearing. As gearing there is, for example, represented a dilferential gear consisting of gear wheels, whereof the wheels, 3 and 4, are visible in the figure. The numeral 4 designates a gear wheel, rigidly connected with a driving member (member 21 in Fig. 2) and with a planetary pinion 3 rolling thereon. The latter is, through a lever 2, pivotally connected with the accumulator 1. When the accumulator is in the tensioned state, upon disengagement of the retaining mechanism, lever 2 will be rotated in a counterclockwise direction. The pinion gear 3 rolls simultaneously on the gear 4.

Fig. 2 shows the connection with the driving shaft 6 and with a driving member 21, which is here indicated by an electric motor. A sprocket wheel 5 of a diiferential gear is rotated by the rolling planetary gear 3. Said gear wheel 5 is rigidly connected with the driving shaft 6 and indicates the double rate of revolutions of the rotary motion of the pinion gear. A switch 8 is, for example, actuated by the driving shaft 6 through a crank 7. When the crank moves upwardly, the switch thereby is connected; when it moves downwardly, the switch is moved to the off position. The switch angle on the crank amounts thus to In this embodiment, locking members 9a and 9b are disposed on the driving shaft 6. In the illustrated state, the left locking member 9a clamps the driving shaft. In order to elfect the disconnectionof this locking member, the respective stop latch 11a is lifted through the .trip coil 10a. Then, the accumulator is released and rotates the driving shaft for a half revolution together with the switch until the right-hand locking member 9b is engaged. By this arrangement, the sequence of the switching is always given positively so that no additional means are required.

The locking can be effected also in another way, as illustrated in Fig. 3. Instead of the locked levers 9a and 9b cam disks 12a and 12b are mounted on the driving shaft 6, which cam disks are held by rollers 14a and 14b seated on knee joint 13a and 1312. When the cams rotate, the roller 14a with the knee joint 13a is pushed down by cam disk 12a until at the lowest point it clamps the cam disk 12a and thus the driving shaft 6. The entire motion is damped by damping devices 15a and 15b, each of which may consist of piston and cylinder. The release is effected in that the knee joint 13a is, for example, magnetically released, as indicated by the arrow. The tensioning of the knee joint is effected by a spring 16a and a lever 1711. Similarly cam disk 12b, mounted on shaft 6 oppositely to disk 12a, actuates roller 14b and knee joint 13b.

During the disconnection, the accumulator spring reduces its force. Thus the torsional moment on the driving shaft ditfers according to the condition of the accumulator. This is generally permissible for smaller switches. In switches of great current intensity, this could show disadvantageous effects. Hence, it is preferred, according to the invention, to provide a special means whereby the magnitude of the torsional moment, alfecting the switch through the driving shaft, is deliberately predetermined. To realize this, the point of application of spring tension can be so displaced that the lever arm of the torsional moment becomes larger or smaller. It is possible to allow the lever arm of the torsional moment to become larger so that the torsional moment remains constant during the entire lift. Thus the lever may then be enlarged just for an amount corresponding to the diminution of the springiness due to the gradual disengagement. However, it can also be modified so as to produce a great torsional moment for the disconnection, while for the engagement a smaller torsional moment is produced since even the power consumption is smaller therefor; Hereby, the spring can be utilized to still better advantage.

A construction of this variable lever arm is shown in Fig. 4. Here is represented a cam plate 18, with the case the dimension of the effective lever arm on the cam plate is small (20). When the spring (accumulator) 1 is disconnected, the cam plate rotates along, whereby the effective lever arm is enlarged. By another shaping of the cam plate, the lever arm can be made smaller in an intermediate position so that asmaller torsional moment is available for the engagement than for the disengagement.

The accumulator may be driven either by hand or by a motor 21 (Fig. 2). According to the inventive idea, the motor needs to work always in the same rotating direction to lift the accumulator. If, for example, the motor fails, the switch must be lifted by hand, so that couplings must be provided for the existing constructions. According to the inventive object such disconnectable couplings may be omitted. 'It appears necessary to combine only the manual drive through-astopping latch with the gear of the motor lift.

The inventive idea can, likewise, be applied to switches improvement which comprises a first gear connected to the driving shaft of the switch, a differential gear system including a planetary gear cooperating with said first gear, means connecting said planetary gear to said accumulator, and means including a second gear cooperating with said planetary gear for initially tensioning said accumulator.

2. Switch actuating means as defined in claim 1 wherein the force of the accumulator actuates the driving shaft in such a manner that a half rotation of the driving shaft is always available for the connection and disconnection switch operations.

3. In switch actuating means utilizing an accumulator wherein the engagement and disengagement of the switch contacts are efiected through a rotary driving shaft, the improvement which comprises a first gear connected to the driving shaft, a differential gear system including a planet-sq cooperating with said first gear, means connecting said planetary gear to said accumulator, and stop latch means for releasably positioning the drive shaft at definite angular positions about its longitudinal axis, said step latch means comprising cam disks displaced approximately 180 on the drive shaft, and roller {answer means cooperating with said cam disks,-- said roller follower means including damping devices econnected to the followers by means of controllable knee joints.

4. In switch actuating means utilizing an accumulator wherein the engagement and disengagement of the switch contacts are effected through a rotary driving shaft, the improvement which comprises a first gear connected to the driving shaft of the switch, a differential gear system including a planetary gear cooperating with said first gear, and means connecting said planetary gear to said accumulator comprising a cam plate secured to said planetary gear and a follower element connecting said camplate to the accumulator so that the torsional moment affecting switch operation may be controlled to a predetermined extent.

' 5. Apparatus as defined in claim 4 wherein the torsional moment affecting the switch is greater in disconnection than in connection as a result of the corresponding shape of the cam plate.

' 6. Apparatus as defined in claim 1 wherein said means for initially tensioning the accumulator includes motor driving means.

7. In switch actuating means utilizing an accumulator wherein the engagement and disenagement of the switch contacts are effected through a rotary driving shaft, the improvement which comprises a first gear connected to the driving shaft of the switch, a differential gear system including a planetary gear cooperating with said first gear, said planetary gear being rotatably supported at one end of a lever element rotatably mounted intermediate its ends on said driving shaft, means connecting the other end of said lever element to the accumulater, and stop latch means for releasably positioning the drive shaft at definite angular positions about its longitudinal axis upon the release of energy from the accumulator.

References Cited in the file of this patent UNITED STATES PATENTS 2,745,515 Pelenc May 15, 1956 

